Relative role of species and age effects of wheatgrasses on the oversummering abundance of Russian wheat aphid Academic Article uri icon

abstract

  • The relative role of species and age effects of wheatgrasses on the oversummering abundance of Russian wheat aphid was studied in a field experiment. The number of Russian wheat aphids was compared on four wheatgrasses in their first and fifth year of growth in grassland conditions (placed side-by-side in small plots) during the summer of 2000. The wheatgrasses were intermediate wheatgrass, Thinopyrum intermedia, cultivar 'Oahe'; slender wheatgrass, Elymus trachycaulus, cultivar 'Pryor'; thickspike wheatgrass, Elymus lanceolatus, cultivar 'Critana', crested wheatgrass, Agropyron cristatum A. destertorum, cultivar 'Hycrest'; and a field-collected crested wheatgrass. At the last sampling date at the end of July, aphids were much more abundant on the field-collected crested wheatgrass than on the other wheatgrasses, and plant age affected aphid abundance on selected wheatgrasses. First-year growth of intermediate wheatgrass had more aphids than fifth-year growth of intermediate wheatgrass whereas the field-collected crested wheatgrass in its fifth year had more aphids than in its first year. In comparing the relative role of species and age effects of wheatgrasses on Russian wheat aphid, analysis of model variation associated with the cultivar effect, the plant age effect, and the cultivar by plant age interaction was 17, 0.1, and 4.8%, respectively. There was a maximum 42-fold difference in number of aphids found on the five wheatgrasses, and a maximum 8.3-fold difference in number of aphids found on first-versus fifth-year growth of the wheatgrasses. In regard to Russian wheat aphid oversummering on wheatgrasses and their potential impact on nearby wheat acreage, we conclude that both cultivar and plant age factors may affect the oversummering abundance of Russian wheat aphid, but the principal concern from a land management perspective is cultivar selection.

published proceedings

  • Journal of Agricultural and Urban Entomology

author list (cited authors)

  • Brewer, M. J., & Noma, T.

complete list of authors

  • Brewer, MJ||Noma, T

publication date

  • July 2002